It is now generally established that cellular regulatory responses to a number of stimuli involve receptor occupancy, alterations in cytoplasmic calcium and pH levels, and subsequent protein phosphorylation reactions. Several recent developments have dramatically improved our ability to dissect and characterize these regulatory pathways. Central among these developments is the adaptation of digital image analysis techniques for use in biological system. We request funds to purchase a Magiscan image analysis system with accessories to provide the capabilities for the production and real time analysis of: (1) light and fluorescence microscopic images, (2) two-dimensional polyacrylamide gel electrophoretograms; and (3) autoradiographic patterns developed from receptor-binding assays. This image analysis system will be utilized to investigate: (1) the roles of altered intra- cellular (Ca2+) and pH, as well as protein phosphorylation reactions, in the regulation of cellular electrolyte and volume homeostasis and amino acid transport; (2) the mechanism of differential gonadotropin release from the anterior pituitary gland; (3) the association of intracellular Ca2+ and pH changes to the modulation of the metabolism of pulmonary surfactant induced by platelet activating factor; (4) the neurochemical mechanisms underlying chronic barbiturate dependency and experimentally- induced Parkinsonism; and (5) the internalization and intracellular processing of peptide hormones by isolated hepatocytes. The purchase of this equipment would greatly extend the techniques available to the Users' Group for investigating the diverse and important physiological questions addressed by the studies outlined here. Each of these studies represents a powerful extension of investigations described in their currently funded PHS grants.